Lecture 25

Question 1

As the adaptive immune sytem progresses to kill off an infection, how are the cells adapting?

Answer 1

More cells are specific to the pathogen (greater quantity)

Cells are more specialised (high affinity antibody or functionally polarised- greater quality)

Question 2

Immunological memory definition

Answer 2

A small pool of specialised memory cells that develop during the adaptive immune response and persist in the absence of the antigen that originally induced them

Question 3

Where do short lived plasma cells reside?

Answer 3

The lymph node or spleen

Question 4

Where do long lived plasma cells reside?

Answer 4

In the bone marrow

Question 5

What B cells are a source of long-lasting high-affinity class-switching antibody?

Answer 5

Long-lived plasma cells

Question 6

How long are long-lived cells around for? What are they good at preventing?

Answer 6

Months. Good at preventing reinfection during an epidemic.

Question 7

Where do memory B cells arise from?

Answer 7

Arise from the germinal center reaction

Question 8

How are memory B cells different from other B cells?

Answer 8

They have inherited the genetic changes from the germinal center reactions

• they express high affinity antibody (already undergone somatic hypermutation)
• they have undergone antibody class switching

They also express higher levels of MHC II and co-stimulatory molecules than naive B cells

Question 9

Where can memory B cells be found in the body?

Answer 9

Populate the spleen and lymph nodes and circulate through the blood

Question 10

How often do memory B cells divide?

a. every week
b. once a year
c. when other memory B cells divide
d. very very slowly

Answer 10

d. very very slowly (if ever)

Question 11

True or false: Memory B cells secrete antibody

Answer 11

False: they express surface Ig but do not secrete antibody

Question 12

What do memory B cells do when they re-encounter antigen?

Answer 12

Quickly regenerate antibody producing plasma cells

Question 13

True or false: memory T cells divide less frequently than naive T cells

Answer 13

False: They divide more frequently

Question 14

memory t cell pool size is dictated by a balance of what?

Answer 14

A balance between cell proliferation and cell death

Question 15

What cytokines are required to keep Memory T cells alive?

Answer 15

IL-7 and Il-15

Question 16

True or false: Memory B and T cells require MHC activation to keep them alive

Answer 16

False: Only memory T cells require MHC activation to keep them alive

Question 17

What are 4 reasons why memory T cells are better then naive T cells?

Answer 17

1. they proliferate more than naice T cells and to lower antigen doses (aka they respond really quickly)
2. they require less co-stimulation for activation than naive cells
3. they produce cytokine faster and retain their polarised phenotype
4. they may be strategically positioned in the tissue where the pathogen is likely to be encountered (e.g. wanting memory T cells against the flu in your lungs rather than your toes)

Question 18

What are the two types of memory T cells?

Answer 18

Central memory and effector memory

Question 19

Which of the following is true

a. both central memory and effector memory T cells express lymph-node homing molecules
b. neither central or effector express LNHM
c. only central memory
d. only effector memory

Answer 19

c. only central memory T cells express lymph-node homing molecules

Question 20

True or false: central memory cells rapidly produce cytokine apon antigenic stimulation

Answer 20

False: effector memory T cells rapidly respond

Question 21

Central memory T cells are FASTER/SLOWER than effector memory cells at producing cytokines upon antigenic stimulation

Answer 21

SLOWER